How to Build a Playground: Lumber
A comprehensive guide to the lumber you’ll need for a DIY playground and play set!
A free-standing structure like the backyard playground I built my children requires a lot of lumber: roughly 6,000 lbs — 3 tons — of lumber! In this post, I’ll provide a list of all the dimensional lumber you’ll need to build this backyard playground so you don’t have to figure out what lumber you need. I’ll also discuss alternatives to lumber that I thought about in the planning phase, explain why I ultimately chose to build the playground out of pressure-treated lumber, and highlight some important considerations when working with dimensional lumber.
As a reminder, we’re building a playground that looks like this:
This is the fifth post of a six-part series covering the fundamentals of building a playground. You can read the other posts in the series through these links: Overview, Materials & Tools, Connectors & Fasteners, Swings & Accessories, and Design Concepts. Additional posts have step-by-step instructions for the actual playground construction; you can explore those on my Playground page.
Wood vs. Composite Lumber
One of the first things I thought about in the planning phase was what material I would build the playground out of. I ultimately decided on pressure-treated wood, but I did consider composite lumber as it has a number of advantages. Composite lumber is made out of plastic (or a mixture of wood and plastic). It is essentially maintenance-free (does not require staining like wood), won’t splinter, and doesn’t attract insects.
Composite lumber has two drawbacks, though. First, it costs much more than traditional wood lumber. And since I needed about 3 tons of lumber, cost was an important factor. For example, a ground-contact, pressure-treated wooden 6″x6″x8′ costs about $40 at Home Depot. That same size in composite lumber (structural-grade) costs about $340. I used 17 of these 6×6 posts, a total of $680 for pressure-treated wood vs. $5,780 for composite lumber. And that’s just the 6×6 posts. Composite lumber simply costs too much.
Second, due to cost I could only use composite lumber for the deck boards. But if I was going to use wood for everything else, it didn’t really make sense to switch to composite lumber for the deck boards. Plus, this is a children’s playground not the deck of a house. Composite lumber is a bit overkill for a project of this nature!
Pressure-Treated vs. Cedar
Since the playground is outdoors, you need wood that is suitable for exterior use. This really came down to a debate between pressure-treated wood vs. cedar wood.
For store-bought playgrounds and playsets, cedar and redwood are the most commonly used woods. I eliminated redwood, as it’s not that common to find in stores like Home Depot. However, cedar wood is pretty easy to find (even for things like 6×6 posts). Playground companies like to tout its supposed benefits: cedar contains natural preservatives, meaning that its naturally resistant to rot/decay and pests. However, in outdoor playgrounds that I’ve seen, I haven’t observed this to be true. In my neighbor’s playset (made out of cedar), carpenter bees routinely bore into it. Cedar is also a low-density wood. It’s really more suitable for finer woodworking applications (cabinets or tables) or maybe deck boards, but not for structural applications.
Pressure-treated wood is generally made from pine (typically southern yellow pine), which is more dense than cedar (western red cedar). Pine does not bend or twist easily, and is perfectly suitable for use in construction projects. The pressure-treatment refers to a process where chemical preservatives are forced into the wood. These chemicals resist rot/decay and insects. Virtually all exterior projects where wood will be outdoors and exposed will use pressure-treated wood. So, for me, using pressure-treated wood was an obvious choice.
Types of Pressure-Treated Lumber
There are two basic types of pressure-treated lumber: above-ground and ground-contact. Ground-contact has twice the level of chemical retention and protection compared to above-ground treated wood. As it’s name implies, it’s meant to be used outdoors where wood will be in contact with the ground – places where you’ll want and need an extra level of protection.
Ground-contact pressure-treated wood does cost slightly more than above-ground. An above-ground pressure-treated 2″x6″x8′ costs about $8, whereas the ground-contact equivalent costs about $12. In my opinion, even if wood won’t be in contact with the ground, if you can afford ground-contact lumber than use it. More wood protection is always welcome. I used ground-contact pressure-treated wood for just about the entire playground.
Kiln-Dried vs. Wet Pressure-Treated Lumber
The term pressure-treated refers to a process in which wood is immersed in a liquid solution of chemical preservatives and then placed in a pressure chamber. The high pressure within the chamber forces the chemical preservatives into the wood fibers.
Since pressure-treated wood is in a liquid solution, it is very wet after the infusion process (picture wood that has been left out in the rain all day). It is not good to use lumber that is still wet in a construction project for two reasons. First, it’s hard to work with. If you try to drill into it, water will come out of the drill hole. It’s also very heavy – a wet 6″x6″x8′ weighs 120 lbs vs 70 lbs for a dry 6″x6″x8′. Second, as the wet lumber dries, it will naturally shrink in size and warp in any number of different ways.
So, people started using kilns to carefully dry pressure-treated wood after the pressure-treatment process. This became so popular that many retailers now offer a KDAT or KD-HT option, which stands for Kiln-Dried After Treatment or Kiln-Dried Heat-Treated. Kilns remove the excess moisture in wet pressure-treated lumber without shrinking or warping the lumber. Definitely try to get kiln-dried pressure-treated lumber if you can. Kiln-dried lumber will be stamped to show that it has been kiln-dried, like this:
If you can’t get kiln-dried pressure-treated lumber, then you’ll need to store the wet lumber and let it air-dry before use.
Storing Lumber and Air-Drying Wet Wood
When storing wood (or air-drying wet wood), ventilation is the most important factor to consider. The best way to keep an airflow channel through stored wood is to arrange it in a lattice pattern like this:
Space permitting, I always store lumber boards like this. And I either store posts like this too, or simply keep them vertical but lean them against the wall.
Helpful tip: if you’re storing wood indoors like I usually do (in my garage), I use one or two fans at max speed and point them at the wood to forcibly circulate air throughout the lattice.
Selecting Your Own Lumber vs. Delivery
For a project of this scale, trekking to a store like Home Depot and filling up the SUV with 3 tons of wood is pretty impractical. It’s also even more impractical when you have your youngest child in a car seat in the backseat of the car. So, I had all the wood delivered from Home Depot to my house.
While delivery is more convenient, it does have an unfortunate consequence: someone else is selecting your wood for you. And they’re not inclined to give you the best wood they’ve got. They’re going to give you whatever they’ve got or whatever they can’t sell. Judging all of the wood that was delivered from Home Depot, I would say about 1/3 was good, 1/3 was just ok, and 1/3 was poor quality.
I wish I could have selected all of the lumber used in this playground project myself, but that simply wasn’t possible. In general, though, if you can go and pick out your own lumber than definitely do that.
Home Depot/Lowe’s vs. Local Lumber Yard
For all previous woodworking/carpentry projects, I have always used lumber from a store like Home Depot or Lowe’s. This has mostly been out of ease and convenience, but also because I haven’t worked on a lot of projects that have required 3 tons of wood before. In retrospect, given that the quality of wood delivered from Home Depot wasn’t the best, I do wonder if wood delivered from a local lumber yard would have been of better quality. They would still be picking out the wood for you, but perhaps they would be more inclined to select and deliver better-quality wood.
If you have experience with wood deliveries from local lumber yards, please let me know in the comments!
Lumber List Overview
The Lumber List is sorted by dimensional lumber size. Quantities needed are provided, as well as the purpose and utility in playground construction. All lumber was ordered from Home Depot, and was ground-contact pressure-treated (unless ground-contact was not offered, in which case it was above-ground).
Lumber List
- 2 in. x 2 in. x 42 in.
- Quantity: 144
- Use: handrail balusters (Mitered 1-End) and ramp traction/steps
- 2 in. x 4 in. x 8 ft.
- Quantity: 24
- Use: handrails and bracing
- 2 in. x 4 in. x 12 ft.
- Quantity: 8
- Use: handrails (for 12 ft. long ramp) and bracing
- 2 in. x 6 in. x 8 ft.
- Quantity: 50
- Use: deck boards and bracing
- 2 in. x 10 in. x 8 ft.
- Quantity: 50
- Use: joists, double 2x support beams, deck blocking
- 2 in. x 10 in. x 12 ft.
- Quantity: 12
- Use: 12 ft. long ramp joists and 12 ft. long double 2x support beams
- 4 in. x 4 in. x 8 ft.
- Quantity: 14
- Use: handrail posts
- 6 in. x 6 in. x 8 ft.
- Quantity: 17
- Use: Structural framing posts
A Note on List Quantities
As with my other playground posts, this was my exact order from Home Depot that I used to build this playground. Hopefully this post takes the guesswork out of figuring out what lumber you need to build a backyard playground, so you can spend less time planning and more time building!
Did you find this guide useful? Have you built a playground or play set? What lumber did you choose to use? Let me know in the comments below!
Read the other five posts on playground construction fundamentals: Overview, Materials & Tools, Connectors & Fasteners, Swings & Accessories, and Design Concepts.
Learn more at ProjectsByPeter.com/Playground
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